Messages in this thread | | | Date | Tue, 10 Apr 2007 18:16:04 -0500 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH 2/3] make kernel threads invisible to /sbin/init |
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Quoting Oleg Nesterov (oleg@tv-sign.ru): > 1. rename reparent_to_init() to reparent_kthread() and export it > > 2. use init_pid_ns.child_reaper instead of child_reaper(current)
Each of these patches looks good to me, but this part in particular is a must-have bugfix.
Just started some tests, if any failures come back I'll report them tonight.
thanks Oleg, -serge
> 3. set ->exit_signal = -1, so init can't see us and we don't use > it to reap the task. > > 4. add reparent_kthread() to kthread() and stopmachine() > > See also > > http://marc.info/?t=117580282200003&r=1 > http://marc.info/?t=95299284800003&r=1 > > Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> > > include/linux/sched.h | 1 + > kernel/exit.c | 16 ++++++++-------- > kernel/kthread.c | 1 + > kernel/stop_machine.c | 1 + > 4 files changed, 11 insertions(+), 8 deletions(-) > > --- 2.6.21-rc5/include/linux/sched.h~2_DETACH 2007-04-05 12:18:28.000000000 +0400 > +++ 2.6.21-rc5/include/linux/sched.h 2007-04-10 21:52:27.000000000 +0400 > @@ -1401,6 +1401,7 @@ extern void exit_itimers(struct signal_s > > extern NORET_TYPE void do_group_exit(int); > > +extern void reparent_kthread(void); > extern void daemonize(const char *, ...); > extern int allow_signal(int); > extern int disallow_signal(int); > --- 2.6.21-rc5/kernel/exit.c~2_DETACH 2007-04-10 21:32:44.000000000 +0400 > +++ 2.6.21-rc5/kernel/exit.c 2007-04-10 21:59:41.000000000 +0400 > @@ -255,7 +255,7 @@ static int has_stopped_jobs(struct pid * > } > > /** > - * reparent_to_init - Reparent the calling kernel thread to the init task of the pid space that the thread belongs to. > + * reparent_kthread - Reparent the calling kernel thread to the init task of the pid space that the thread belongs to. > * > * If a kernel thread is launched as a result of a system call, or if > * it ever exits, it should generally reparent itself to init so that > @@ -264,20 +264,20 @@ static int has_stopped_jobs(struct pid * > * The various task state such as scheduling policy and priority may have > * been inherited from a user process, so we reset them to sane values here. > * > - * NOTE that reparent_to_init() gives the caller full capabilities. > + * NOTE that reparent_kthread() gives the caller full capabilities. > */ > -static void reparent_to_init(void) > +void reparent_kthread(void) > { > write_lock_irq(&tasklist_lock); > > ptrace_unlink(current); > remove_parent(current); > - current->parent = child_reaper(current); > - current->real_parent = child_reaper(current); > + current->parent = init_pid_ns.child_reaper; > + current->real_parent = current->parent; > add_parent(current); > > - /* Set the exit signal to SIGCHLD so we signal init on exit */ > - current->exit_signal = SIGCHLD; > + /* make the task auto-reap */ > + current->exit_signal = -1; > > security_task_reparent_to_init(current); > write_unlock_irq(&tasklist_lock); > @@ -391,7 +391,7 @@ void daemonize(const char *name, ...) > current->files = init_task.files; > atomic_inc(¤t->files->count); > > - reparent_to_init(); > + reparent_kthread(); > > if (!has_rt_policy(current) && (task_nice(current) < 0)) > set_user_nice(current, 0); > --- 2.6.21-rc5/kernel/kthread.c~2_DETACH 2007-04-05 12:18:28.000000000 +0400 > +++ 2.6.21-rc5/kernel/kthread.c 2007-04-10 22:02:31.000000000 +0400 > @@ -82,6 +82,7 @@ static int kthread(void *_create) > sigset_t blocked; > int ret = -EINTR; > > + reparent_kthread(); > kthread_exit_files(); > > /* Copy data: it's on keventd's stack */ > --- 2.6.21-rc5/kernel/stop_machine.c~2_DETACH 2006-10-22 18:24:03.000000000 +0400 > +++ 2.6.21-rc5/kernel/stop_machine.c 2007-04-10 22:04:23.000000000 +0400 > @@ -33,6 +33,7 @@ static int stopmachine(void *cpu) > int irqs_disabled = 0; > int prepared = 0; > > + reparent_kthread(); > set_cpus_allowed(current, cpumask_of_cpu((int)(long)cpu)); > > /* Ack: we are alive */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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